AGE OF THE UNIVERSE - INFLUENCE OF THE INHOMOGENEITIES ON THE GLOBAL EXPANSION FACTOR

For the first time wt calculate quantitatively the influence of inhomo geneities on the global expansion factor by averaging the Friedmann eq uation, In the framework of the relativistic second-order Zel'dovich-a pproximation scheme for irrotational dust we use observational results in the form of the normalization constant fixed by the Cosmic Backgro und Explorer results and ive check different pou er spectra, namely, f or adiabatic cold dark matter (CDM), isocurvature CDM, hot dark matter , warm dark matter, strings, and textures, We find that the influence of the inhomogeneities on the global expansion factor is very small. S o the error in determining the age of the universe using the Hubble co nstant in the usual way is negligible. This does not imply that the ef fect is negligible far local astronomical measurements of the Hubble c onstant. Locally the determination of the redshift-distance relation c an be strongly influenced by the peculiar velocity fields due to inhom ogeneities. Our calculation does not consider such effects, but is con strained to comparing globally homogeneous and averaged inhomogeneous matter distributions, In addition we relate our work to previous treat ments.